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Activation of P2Y1 purinergic receptors (P2Y1Rs) induced calcium influx in rat supraoptic neurons (SON) through stretch inactivated cation (SIC) channels
Author(s) -
Song Zhilin
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1025.12
Subject(s) - biophysics , ruthenium red , chemistry , purinergic receptor , calcium , intracellular , voltage dependent calcium channel , extracellular , receptor , calcium in biology , membrane potential , biochemistry , biology , organic chemistry
Activation of P2Y1Rs contributes to the ATP‐induced increase in intracellular calcium ([Ca ++ ] i ) in SON. Although activation of P2Y1Rs induced release of Ca ++ stores presumably as a result of IP3 production, it also induced a small Ca ++ influx, possibly through plasma membrane IP3 receptors or modulation of other ion channels such as osmo‐sensitive SIC channels. Current studies evaluated the role of SIC channels in P2Y1R induced Ca ++ influx by directly monitoring [Ca ++ ] i changes using live cell calcium imaging. Hypothalamo‐neurohypophyseal explants were loaded with the Ca ++ ‐sensitive dye, fura 2AM, and the change in [Ca ++ ] i in SON was determined by ratiometric analysis of fluorescence emitted by excitation at 340 and 380 nm. Activation of P2Y1Rs by 2‐methyl‐thio‐ADP (2‐MeSADP, 100 μM) induced a large increase in [Ca ++ ] i . The amplitude of the increase was reduced by ruthenium red (RR, 10 μM) and gadolinium (Gd, 100 μM), both of which block mechano‐sensitive channels including the SIC channels. Furthermore, the decay after peak response was much faster in the presence of RR and Gd. These results indicate that activation of P2Y1Rs may modulate SIC channels, thus inducing a small component of influx of extra‐cellular Ca ++ , in addition to release of Ca ++ from intracellular stores. Further studies are ongoing to clarify the underlying mechanisms and functional importance of the Ca ++ influx. Supported by AHA SDG 0735329N.